Electrical supply apparatus



M. ALDEN.

ELECTRICAL SUPPLY APPARATUS,

APPLICATION FILED NOV-12,1917- l,330, l 53 Patented Feb. 10, 1920.

2 SHEETSSHEET I.

WITNESSES LQ ffim, BY L I ATTORNEYS.

M. ALDEN.

ELECTRICAL SUPPLY APPARATUS.

APPLICATION FILED NOV. 12. 1911.

1 ,3 30, 1 53 Patented Feb. 10, 1920.

2 SHEETSSHEET 2.

INVENTOR.

A TTORNEYS.

WI T NESSES:

. UNITED T is PATENT F E MILTON ALDEN, or SPRINGFIELD, raessecnusn'r'rs, Assrelvonro DENTAL ELECTRIC COMPANY, or srnmsrrnnn, massncnusnrrs, A oonronarron or MASSACHU- snr'rs.

1 '0 all. to 700m it may concern:

Be it known that I, MILTON ALDEN, a citizen of the United States of America, residing at Springfield, in the county of Hampden and State of IV assachusetts, have invented certain new and useful Improvements in Electrical Supply Apparatus, of which the following is a specification.

This invention relates to improvements in electrical supply apparatus, such, for ex} ample, as are used by dentists,-surgeons, and others for supplying electrical energy to instruments of various 'kinds.

Electrical instruments have found favor in modern dentistry and surgery and are rapidly coming into extensive use; These instruments, due to'the character of the work for which they are designed, cannot readily be operated at high voltages and are purposely constructed for operation at relatively low voltages to avoid injury to the patient. Generally, however, the only convenient source of electrical energy is the commercial alternating current lighting circuit, the voltage of which is seldom low enough for the purposes desired. Accordingly stepdown transformers are employed to reduce the voltage within the required limits. It is also desirable in dental and surgical instrumentsto be able to vary the voltage as some instruments require higher voltages than others and other instruments, such as cauterizing tools, are operated" at varying voltages depending upon thecharacter of the work to beperform'ed; This necessitates the use of a rheostat or equivalent controlling device. This invention is concerned among other things with the provision" of a. portable compact [apparatus which embodies the essential transformer and rheostat withina single casing and which is arranged for convenient use with electrical instruments without requiring attention on the part of the operator.

An object of the invention isto provide in an instrument ofthe character described holding means in which electrical instruments may be supported for convenientre- I moval and switches in the electricalcircuit of each. instrument arranged. to automatically close and energize the instruments when the latter are removed from their hold ingmeans and' to automatically open and deenergi ze the instruments. as soon asthe latter are replaced.

l which.

ELnoTItr'o'AL sUrrLY Heartless.-

Specification of Letters Patent. t t b; 1 9 0 Application filed November 12,1917. Serial No. '2U1;719.'

out preferred, is shownior illustrative pur- V poses in the accompanying drawii'i'gs, in

Figure l is a side, elevational view otthe apparatus;- y y W Fig. 2 is an enlarged plan view thereof;

Fig. 3 is anen'larged bottom plan view of'thecover-shown' as removed from the'apparatus;

Fig. 4 islan enlarged'top planview of the apparatus with the cover removed;

Fig. 5 isanjenlargedcross sectional view taken on the line 5 -5'Qf Fig. 2 V

Fig.6 is a bottom plan view offth'earm for supportinginstruments used with the apparatus and shows the switch inc'lo'sing casing; A p p M Fig. 7 is a perspective view of theswitch inclosi'ng' casing shown as removedlroi'ii the arm; and I p 8 is. a 'diagrammatical view (of the electrical connections ofthe apparatus."

Referring to these drawings, 7 the ap paratus involves a casing 10', which be suitably 'supported'in' any desired manner as, for example, by a pedestal '11' through the intermediary of a swivel joint indicated conventi'onally at 12. Within the casing .10 is a suitable transformer 13' (Fig. 4) which is adapted, as will appear, for connectionto a suitable sourcejof electrical energy, the supply wires 14: for the transformer passing through a wall of casing 10 and preferably through the pedestal 11, as indicated in v Fig. 1 Theupper'endofcasing'10 is Iin-Q closed by a cover 15 of insulating material and on the bottom face of the cover isa, suitable rheostat, such asa helical,coil"16 of resistance wire bent into: circular. form and secured to the cover. The rheo s'tatha's an arm 17 'adaptec'l] to play over the lower ends or"; coil 1'6 Which arm is mounted in cover j 15jj and is rotatable by, fa knjob 18' on the top of the cover. A pointer l9imovable v with arm 17 plays over a dial 20, which may be graduated in suitable units as volts, 7

' a pin 40 which has a rounded lower end for example. Also mounted on the cover 15 are twoipairs of binding posts 21 to which the flexible cords 22 of suitable electrical instruments 23 are removably attached. The instruments may be of any suitable type and the left and right hand instruments,

which are shown herein merely for illustrative purposes, represent a combined lamp and mirror and a cauteriz ng tool, respectively.

The electrical apparatus described is connected as indicated in Fig. 8, the connections having been omitted in the other figures to avoid confusion with mechanical structure. The primary and secondary coils of transformer 13 are indicated at 24 and 25 and one end of the former is connected to a source of alternating current. The other end. of coil 24: is connected by wire 26 to two upper fingers 27, which engagefingers 28 as indicated, the lower fingers '28 being electrically connected together and to the source of current by a wire 29. Thus, when either finger 27 engages its finger 28 the transformer 13 is energized.

One terminal of secondary coil 25 is connected by a wire 30 to two upper fingers 31 which are adapted to engage with lower fingers 32. The right hand finger 32 is electrically connected by a wire 33 with one of the binding posts 21 of the right hand pair and the lefthand finger 32 is similarly connected to one binning post 21 of the left hand pair. The other, terminal of coil 25 is connected by a wire 34 to the rotatable contact arm 17 of the rheost-at and the coil 16 of the latter is connected by a wire 35 to the other binding post 21 of each pair. If one of the instruments 23 requires a somewhat lower voltage than the other a constant resistance 36 may be interposed in the circuit to its binding posts 21, as indicated. When either finger 31 engages its finger 32, the instrument 23 connected in the circuit therewith is energized.

\ The fingers 27, 28, 31, and 32 are arranged in right and left hand sets, each set being supported from a, common insulating block 37, which, as indicated in Fig. 4, closely fits between an end of transformer 13 and one end wall of casing 10, and as shown in Fig. 5is held laterally in position by engagement with the side walls of the casing.

from another, as indicated in Fig. 5, and

each set of fingers protrudes laterally moval.

The.

several fingers aresuitably insulated one Slidable in the shank of each clip 39 is resting upon an insulating strip 41 secured to and extending from the end of a finger 32. Each finger 28 and 32 extends beyond the fingers 27 and 31, respectively, thereabove and these extended ends are separated by an insulating block 42. The fingers 28 and 32 are so constructed as to spring upwardly into engagement with their fingers 27 and 31, respectively, and thus an instrument 23, when removed from its clip 39, immediately becomes energized, and, when replaced, it is automatically deenergized. The spring action of the upper fingers 32 is utilized also as a means to force pins &0 upwardly in clips 39 when an instrument isremoved.

In order to inclose the fingers projecting through openings 38 and to close the latter, housings 4:3 are provided. The latter may be advantageously formed from a single piece of metal pressed into the form best shown in Fig. 7. As there shown, the housing is open at thetop and at one end. Along each upper edge of the housing an outwardly turned flange at is provided and formed in each fiange adjacent the open end of the housing is a notch l5. The described arm 39 has in its lower face two pairs of headed pins 4:6 fixed to the arm in spaced relation therealong. The heads of pins 46 are spaced below arm 39' just sufficiently to receive therebetween the flanges {let (Fig. 5). The pins tfi of each pair are spaced laterally just sufficiently so that the housing may be slid along the arm with the outer edge of each flange bearing against the inner edge of a pin. The top opening of the housing 43 is then closed by the arm 39 and the open end of the housing abuts casing "10 to close opening 38. The distance between flanges 44 is made slightly greater adjacent the open end than adjacent the closed end of the housing. The

sides of the housing adjacent its open end tions into engagement with the pins. It will thus be seen that the housing maybe removably held in position on the arm and" that it-maybe readily removed and replaced to permit convenient inspection and repair of the contact fingers. V

An important feature of the invention consists in the arrangement, whereby each instrument is automatically energized when it is removed from its holder and auto matically deenergized when replaced therein. It is to be noted particularly that not only are the secondary circuits to the instruments opened when an instrument is placed within the holder, but when both instruments arereplaced the supply circuit to the primary coil of the transformer is also opened. The particular mechanism for accomplishing this result is also of importance in an instrument of this type. The mechanism is simple in'construction and advantageously arranged for positive and efficient action without a multiplicity or complication of parts.

Thus an electrical supply apparatus of generally simplified and improved construction has been provided. Itis recognized that modifications may be made in the structure herein described for illustrative purposes without departing from the scope of the invention which is defined by the ap pended claims rather than by the foregoing description;

What I claim is l a V 1. An apparatus of the class described, comprising, a casing, aplurality of holding means thereon to removably support electrical instruments, sets 01": terminals on the casing to which said instruments may be electrically connected, a transformer the primary coil of which'is adapted for connection at one end to a source of electrical energy, an electrical circuit from the secondary coil of the transformer to each setof terminals, a switch in each circuit a1; ranged to close automatically, and means associated with each holding means to open its switch when an instrument is positioned in its holding means, whereby the instrument is automatically deenergized, another,

a casing, an arm projecting therefrom,

means .on the arm to reinova-bly support an electrical instrument, a switch comprising -normally engaged spring contact fingers supported at one end in the casing and protruding at the other end through the casing and below said arm, a slidable pin in the clip, an extension on one of said fingers adapted to support an end of said pin, the other end of the latter adapted to be engaged as an instrument is inserted in the clip and depressed to open said switch, and a housing removably secured to said arm and inclosing said fingers, the housing being constructed and arranged for removal from without the casing, whereby the contact fingers may be convenientlyinspected, adjusted, and repaired.

MILTON ALDEN. 

